If you happen to feel tired, lethargic or sleepy after a meal, you may be experiencing what is informally known as food coma. The medical term for this postprandial somnolence, which literally means, sleepiness after eating. There’s not been much research around this phenomenon, but experts have espoused some theories that could explain why food tends to wear you down.
Having a big meal
Some of the few studies into this occurrence show that people experience exhaustion and sleepiness after having big meals. Healthline reports that research that analysed the men who ate pizza found that:
Those who overate reported less energy and more physical tiredness, sleepiness, and lethargy in the 4 hours after eating, while those who ate only until comfortably full had no adverse effects.
Another study focusing on the effect of meals on drivers found that those who had heavy meals were more likely to deviate from their lanes than those who had less caloric-dense meals.
The health news outlet also referenced a recent study that discovered a decrease in blood flow to the brain in people who skip breakfast.
High carb meals
Apart from the size of the meal, another theory around why this happens is that eating a meal high in carbohydrates and/or sugar (white bread, white rice, pasta) produces a spike in your blood sugar, according to Women’s Health. This causes a crash in your system, making you to feel knackered after eating. However, this does not mean that you should avoid carbohydrates. The magazine explains:
Portion size also matter, especially when it comes to theory two. So eating high-carb and high-sugar foods might not necessarily trigger a food coma unless you eat a lot of them at once.
Some people report being in food coma for as long as four hours. The duration can be impacted by alcohol intake and sleep deprivation, Healthline adds.